Control of torque and fluid flow in sealed drives



May 3, 1960 M. F. PETERS 2,934,920

CONTROL OF TORQUEYAND mum FLOW IN SEALED DRIVES Original Filed April 26, 1954 FLUID WT FLUID IN INVENTOR. Melville F. Peters ATTORNEY out exceeding the elastic limit of the material.

CONTROL OF TORQUE AND FLUID FLOW IN SEALED DRIVES Melville F. Peters, Livingston, NJ.

Original application April 26, 1954, Serial No. 425,669, new Patent No. 2,870,617, dated January 27, 1959. Divided and this application November 14, 1958, Serial No. 773,881

3 Claims. or. 64-32 This invention relates to combining flexible fluid seals with universal joints, couplings andother types of supporting structures and in particular with flexible assemblies which allow the two ends of the assembly to move independently of each other in all directions except the direction of rotation which is used for transmitting torque, and is a division of an application filed April 26, 1954,

, by Melville F. Peters, Serial No. 425,669, now Patent No.

When bellows are used for the dual purpose of forming a fluid seal and transmitting the torque or twisting forces between two rotating hollow shafts or tubes, the stresses developed in the bellows will be high if the operation requires relatively large torques and bellows displacements. The stresses developed in the bellows can be reduced to values which are well below the proportional limit allowed for the material in the bellows, if a flexible supporting structure is placed between the two ends of the bellows to transmit the torque between the rotating shafts and to use the bellows mainly for sealing and transmitting the fluid. It is therefore the first object of the invention to combine a flexible mechanical structure with a flexible fluid seal, so that the unit may be used to transmit mechanical and fluid energy without stressing the component parts of the assembly beyond the elastic limit.

When power is transmitted through a universal joint there will be small angular rotation between the two ends of the flexible element and as these contacting parts wear, this angular rotation will increase. When the joint must be hermetically sealed so that fluid can be retained or transmitted between the two ends of the joint, the rotating elements may be enclosed in a bellows which is attached to suitably arranged shoulders, so that the bellows and shoulders confine the joint in a fluid-tight chamber. To

be sure that the universal joint will not bind with change in temperature it is necessary to allow clearance between the rotating surfaces so that a small angular d.splacement always takes place in the joint when there is a change in the angular accelerations. This angular displacement is greater than the conventional bellows can withstand with- If the bellows is modified so that 'it permits an angular rotation of at least degrees without exceeding the elastic limit of the material in the membranes, the combination of a flexible fluid. seal which allows both rotation and extension can be combined with the universal joint, so that the stresses developed in the flexible seal will remain below the elastic limit during the transmission of energy through the joint. It is therefore the second object of the invention to combine a universal joint with a flexible fluid seal which can be extended or rotated through a small angle, between the two ends of the joint.

In some installations it is necessary to transmit power through fluid-tight chambers where bearing and moving contacting surfaces can not'be tolerated. When the rotating forces or torques are great enough to require a reinforcing structure to act in conjunction with a bellows,

States Patent it is necessary to select a reinforcing structure which does not have rubbing surfaces. This reinforcing structure must maintain the stresses in the bellows below the elastic limit and at the same time allow the rotating shafts to move independently of each other in all directions except the direction of rotation, which is the direction by which power is transmitted through the flexible sealing assembly. It is therefore the third object of the invention to connect the flexible fluid seal to the adjacent ends of the rotating elements to form a fluid tight chamber and to place a supporting structure between the adjacent ends of the chamber, so that the supporting structure permits a movement of each element which is independent of the other element, except in the direction in which the rotating forces are transmitted through the flexible assembly.

When the flexible fluid seal is subjected to a relatively high internal fluid pressure and the axis of rotation of the two shafts are at an angle less than 11', the bellows will be'deformed during each revolution of the two shafts more than is required to correct for the misalignment of the shafts. This deformation of the bellows can be controlled by surrounding at least a portion of the fluid seal with a restraining element. object of the invention to provide a restraining surface so that the bellows can not be deformed beyond a predetermined value.

When the axisof rotation of one end of the seal is parallel but not in line with the axis of rotation of the-other end, the transmission of mechanical power through the seal can be done with a flexible fluid coupling. If the operating temperatures are high, the contacting moving surfaces must be eliminated and the transmission of mechanical power from one rotating shaft to the other shaft must take place through a flexible mechanical coupling which allows the two shafts to move independently of each other 'in all directions except the direction of rotation common to both shafts and this direction lies in the plane normal to the axis of rotation. Since the bellows can not withstand shear and consequently it can not withstand an appreciable movement normal to its axis, provision must be made for at least one end of the bellows to move freely. This can be accomplished by putting a rotary or sliding seal on the free end of the bellows. It is therefore a fifth object of the invention to conduct fluid between two rotating elements by attaching not more than one end of the bellows to one of the rotating elements and to form a sliding seal between the free end of the bellows and the second rotating element and to transmit the mechanical forces or torque applied to one rotating element to the second element by using a mechanical structure which permits movement in all directions except the rotary motion which is normal to the axis of the rotating shaft.

In the drawing:

Figure 1 is a cross sectional view of a conventional type of universal joint surrounded by a flexible fluid seal which can be elongated and also rotated through a fractional part of 2 radians, an embodiment of the invention.

In Figure 1 the universal joint consists of two yokes 2 and 2' mating with the spherical segment 3 and pin 4 passing through the spherical segment and the two yokes, so that the rotation of the shaft 1 in the direction of the arrow 5, will cause the hollow shaft 1 to rotate in the direction of arrow 5' and in like manner if the rotation of the hollow shaft 1 is reversed, the direction of rotation of shaft 1' will be reversed, but the combination of the yokes 2, 2', the spherical segment 3 and Pin 4, will permit the two hollow shafts or tubes to operate at an angle 06- At 8 and 8' is secured the two ends of bellows 6 hereinafter referred to as the bellmets to the two plates or shoulders 9 and 9' which are secured to 1 and 1' respectively at 10 and 10'. The bellmets consists of a It is therefore a fourth 3 plurality of plates 7 welded together on their outer peripheries and bonded together on their inner peripheries at 11 with silastic resin as described in my patent applicationfiled July 2, 1951, Serial Number 239,607. Tests the flexible sealing element of the universal joint, since rapid accelerations of shaft 1', with a consequent small rotation of one end plate with respect to the other plate occur.

When the universal joints are new and the angular rotation between the two ends of the seal are small, a bellows may be bonded to shoulders '9 and 9 at 10 and 10', with a short but sometimes satisfactory life. An example of such an installation is the'guided missile where the operating period is a matter of minutes.

Having thus fully described the invention, what is claimed as new and desired tobe'secured by Letters Patent of the United States is:

1. A torque transmitting mechanism comprising a pair of rotatable fluid conduits having apositioned axially spaced flanges, a bellows assembly interconnecting said flanges, said bellows assembly comprising a series of plates welded together on their outer peripheries in pairs and alternately bonded together with a resilient material 4, on their inner peripheries, coupling means within the bellows assembly joining the conduits, said bellows assembly being capable of an angular displacement greater than the angular displacement of the coupling means.

2. A torque transmitting mechanism comprising, a pair of rotatable fluid conduits having apositioned axially spaced flanges, a bellows assembly interconnecting said flanges, said bellows assembly comprising a series of plates welded together on their outer peripheries in pairs and alternately bonded together with a resilient material on their inner peripheries, coupling means within the bellows assembly joining the conduits, a fluid conducting bore in said coupling means leading from the conduits to the interior of the bellows assembly, said bellows assembly being capable of an angular displacement greater than the angular displacement of the coupling means.

3. A bellows assembly capable of rotation in a direction normal to its axis comprising a plurality of centrally bored plates, said plates being welded together at their outer peripheries into pairs and a bond of resilient material connecting the pairs of plates at their inner peripheries into a bellows assembly.

References Cited in the file of this patent 

